Not all powder coating is the same. Some use proper preparation and a high zink primer layer and hold up well. A poor powder coat job doesn't hold up as well as paint.

it's considered a non-structural weld that litterally just seals the connection so that water can't get in somewhere and rust.

We do it all the time on hot dipped galvanized parts becasue the galv is not viscuos enough to get into tight crevises, so instead we "seal weld" the areas so that it won't be a problem later. This is very common and the welds are as small as you can make them.

xdguy
AWS A3.0, Standard Welding
Terms and Definitions, defines a seal weld as: “Any weld
designed primarily to provide a specific degree of tightness
against leakage.” The purpose of a seal weld may
be to contain a fluid – either gaseous or liquid. In the
mechanical and structural fields, seal welds are used most
often not to prevent leakage out of a container, but to prevent
entry of a fluid into a space where some type of
harmful behavior, often corrosion, is expected to occur. In
these fields, seal welds are frequently used to preclude
moisture and oxygen-laden air and water from entering
that cavity.
Seal welds may be specified on parts to be galvanized to
prohibit pickling acids and/or liquid zinc from entering into a
specific region. For architecturally exposed steel that is to
be painted, seal welds may be specified to prevent unsightly
rust bleeding. Seal welds may be required for some
applications where the sealed joint is more conducive to
cleanup than an exposed joint would be. Food processing
facilities are one such example.
The characteristic common to all of the aforementioned
examples of seal welds is as follows: none of them are
placed for traditional strength-related reasons, and for this
reason, caution should be exhibited when seal welds are
specified. In some cases, the application of a seal weld
may result in a conflict of code requirements. In others,
the seal weld may perform structural functions that were
unintended, resulting in undesirable load paths. Seal
welds may affect inspection practices, in particular, the
interpretation of ultrasonic inspection results. Finally, seal
welds may be treated in a casual manner by those
responsible for making them, resulting in weld quality
problems.
So keep the cracks painted.
Again Welcome to the Forum
Marshall

I'll weld around my balusters completely. What you have to remember is when you weld just opposite sides and paint the paint may or may not seal the slight gap between the baluster and the gate frame. Condensation, rain will get in this slight gap and within days or weeks you will see rust streaks. You would think powder coating would take care of this "slight" problem. However, due to the magnetic fields in the tight corners, the non-welded area where the baluster meets the frame, the powder will have a hard time sticking to these area's. The end result, moisture get's in and rust streaks come out. I have seen this first hand and have a VERY experienced powder coater who enlightened me about the problems with getting into tight corners. Think he compared it to the two magnets, both North poles pushing away from each other, said because of the magnetic/electrical field the powder does not adhere well.

So, in short, all of my handrail, gates are welded 360 degree's on all balusters, gives that area so the powder coat can stick effectively. Actually, all seams and open areas like that, under the cap rail, lambs tongues and so on get welded fully as I do not wish to see rust streaks on new handrail or gates and I'm sure my clients don't either. A bit more time consuming. Nice work on the gate though, looks real good!!